How to make a number or letter just out of dots (emitting light)?
Add "text", change it to your desired text, then "convert text to mesh".



Subdivide a few times using W > "Subdivide".



Add a sphere, and resize it, making sure the sphere's diameter is smaller than the distance between vertices. (This is for later if we choose to use the "0's" vertices as the sphere distribution control point.) 



Add the sphere's material.



Extrude the text to give it some depth, and add a particle system.
In edit mode, I can see the number of vertices for the mesh; use that number as the number of emitted particles.

 

Playing with the "start" and "end" will change the placement of our particle spheres.



It looks a little awkward though (since the vertices aren't evenly spread), so you can choose to use "volume" and "grid" instead. Don't forget to adjust the resolution.



Convert the particle system in Properties> Modifiers, then head back to Properties> Particles and remove it. You will then have thousands of separate little glowing spheres making up your text.



Rendered View:



Choose whichever placement suits you best (vertices, volume, etc.), using a particle system gives you lots of flexibility.